Genetic Variants Modulating CRIPTO Serum Levels Identified by Genome-Wide Association Study in Cilento Isolates

Abstract

Cripto, the founding member of the EGF-CFC genes, plays an essential role in embryo development and is involved in cancer progression. Cripto is a GPI-anchored protein that can interact with various components of multiple signaling pathways, such as TGF-β, Wnt and MAPK, driving different processes, among them epithelial-mesenchymal transition, cell proliferation, and stem cell renewal. Cripto protein can also be cleaved and released outside the cell in a soluble and still active form. Cripto is not significantly expressed in adult somatic tissues and its re-expression has been observed associated to pathological conditions, mainly cancer. Accordingly, CRIPTO has been detected at very low levels in the plasma of healthy volunteers, whereas its levels are significantly higher in patients with breast, colon or glioblastoma tumors. These data suggest that CRIPTO levels in human plasma or serum may have clinical significance. However, very little is known about the variability of serum levels of CRIPTO at a population level and the genetic contribution underlying this variability remains unknown. Here, we report the first genome-wide association study of CRIPTO serum levels in isolated populations (n = 1,054) from Cilento area in South Italy. The most associated SNPs (p-value<5*10-8) were all located on chromosome 3p22.1-3p21.3, in the CRIPTO gene region. Overall six CRIPTO associated loci were replicated in an independent sample (n = 535). Pathway analysis identified a main network including two other genes, besides CRIPTO, in the associated regions, involved in cell movement and proliferation. The replicated loci explain more than 87% of the CRIPTO variance, with 85% explained by the most associated SNP. Moreover, the functional analysis of the main associated locus identified a causal variant in the 5’UTR of CRIPTO gene which is able to strongly modulate CRIPTO expression through an AP-1-mediate transcriptional regulation.

Variation rs2235503 C > A Within the Promoter of MSLN Affects Transcriptional Rate of Mesothelin and Plasmatic Levels of the Soluble Mesothelin-Related Peptide

“…However, given the limited number of MPM patients recruited in the present study, this result should be carefully evaluated and more work involving additional cohorts is needed to elucidate the prognostic role of the rs2235503. Then, we assessed whether the performance of SMRP could be improved when taking into account the subjects' genetic background, in agreement with previous findings for other biomarkers (Cramer et al, 2003;Gudmundsson et al, 2010;Enroth et al, 2014;Ruggiero et al, 2015;Wang et al, 2018). Notably, we found that the AUC for individuals carrying the rs2235503-C/C genotype was higher (0.915) than that of carriers of the A-allele (0.798) and higher as compared to the whole population (0.877).…”

“…However, we believe that the genetic background could play a prominent role in this context. An increasing number of studies, by showing the importance of genetic variations in altering the concentration and the accuracy of several biomarkers, strongly support this idea (Cramer et al, 2003;Gudmundsson et al, 2010;Enroth et al, 2014;Ruggiero et al, 2015;Wang et al, 2018). Furthermore, we showed for the first time that single nucleotide polymorphisms (SNPs) located within the 3 -UTR of the MSLN gene could affect the SMRP levels through a miRNA-mediated mechanism (Garritano et al, 2014).…”

A Multidisciplinary Review of the Roles of Cripto in the Scientific Literature Through a Bibliometric Analysis of its Biological Roles

“…When challenged with a colon-specific carcinogen, Cripto heterozygous mice exhibited a higher incidence of colon cancer compared to Cripto wild-type mice [111]. Polymorphisms and mutations in the TDGF1 locus have been linked to different medical conditions and assessing the TDGF1 genetic status was shown to improve cancer patients' risk stratification, as well as produce information about potential genetic disorders [2,112,113]. For instance, Cripto promoter methylation was shown to discriminate among different subtypes of testicular germ cell tumors [112].…”

“…However, its use as a pan-cancer serological marker should be further investigated in order to establish a definite threshold for baseline levels of circulating Cripto. In this regard, a few polymorphisms in the TDGF1 promoter have been linked to a significantly reduced level of circulating Cripto in a genome-wide association study of about 1500 individuals [113].…”

Developmental signaling pathways regulating mammary stem cells and contributing to the etiology of triple-negative breast cancer

“…Additionally, soluble Cripto-1 levels are elevated in the plasma obtained from colon, lung, glioblastoma, and BC patients, what suggests that Cripto-1 levels in human plasma or serum may have potential clinical diagnostic and prognostic significance [ 7 ]. A genome-wide association study for Cripto-1 serum levels performed in an isolated human population, aiming to identify genetic variants associated with the levels of circulating Cripto-1 protein in the serum, confirmed its fundamental role in embryonic development and cancer [ 66 ]. Moreover, GRP78/BIP is expressed on the surface of tumor cells [ 67 ] where it preferentially binds to GPI-anchored proteins [ 68 ], and it has been shown that Cripto-1/GRP78/BIP complex increases tumor growth [ 69 ].…”